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二进制中1的个数输入一个整数 n ，输出该数32位二进制表示中1的个数。其中负数用补码表示。public int NumberOf1(int n) { int count=0; while(n!=0){ count++; n=n&(n-1); } return count; } 如果一个整数不为0，那么这个整数至少有一位是1。如果我们把这个整数减1，那么原来处在整数

标题

Duplicate Calculation in RecursionMemoization is an optimization technique used primarily to speed up computer programs by storing the results of expensive function calls and returning the cached result when the same inputs occur again. (Source: wikipedia

NoSql:not noly sql泛指非关系型数据库特点：方便扩展大数据量高性能数据类型是多样性的，不需事先设计数据库NoSql四大分类：kv键值对 redis文档型数据库列存储数据库图关系数据库redis：remote dictionary server远程服务字典定义：c语言编写，支持网络，可基于内存可持久化的日志型，kv数据库特性：多样的数据类型持久化集群事务有16个数据库，默认使用第0个redis的单线程的，但速度还是快的redis是将所有的数据全部放在内存

Principle of Recursion

ConclusionConstruct Binary Tree from Inorder and Postorder TraversalGiven two integer arrays inorder and postorder where inorder is the inorder traversal of a binary tree and postorder is the postorder traversal of the same tree, construct and return the

Solve Tree Problems RecursivelyMaximum Depth of Binary TreeA binary tree’s maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.class Solution { int max=0; private void maximum_depth(TreeN

a

Doubly Linked ListDesign Doubly Linked ListDesign your implementation of the linked list. You can choose to use a singly or doubly linked list.A node in a singly linked list should have two attributes: val and next. val is the value of the current node,

Reverse Linked ListGiven the head of a singly linked list, reverse the list, and return the reversed list.

single linked list

ConclusionHeight CheckerA school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected

in-Place OperationsReplace Elements with Greatest Element on Right Sidepublic int[] replaceElements(int[] arr) { for (int i=0;i<arr.length;i++){ int Gnum=-1; for (int j=i+1;j<arr.length;j++){ if(arr[j

ArrayCheck If N and Its Double ExistGiven an array arr of integers, check if there exists two integers N and M such that N is the double of M ( i.e. N = 2 * M).public boolean checkIfExist(int[] arr) { boolean flag=false; for (int a :

ArrayRemove ElementGiven an array nums and a value val, remove all instances of that value in-place and return the new length.Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.T

ArrayDuplicate ZerosGiven a fixed length array arr of integers, duplicate each occurrence of zero, shifting the remaining elements to the right.Note that elements beyond the length of the original array are not written.public void duplicateZeros(int[]

ArrayMax Consecutive OnesGiven a binary array nums, return the maximum number of consecutive 1’s in the array. public int findMaxConsecutiveOnes(int[] nums) { int count = 0; int[] result =new int[nums.length]; int